The present invention relates to a hinge device which connects the body of a portable telephone or the like with its cover (frame) rotatably.
As disclosed in the Japanese Patent Unexamined Publication No. 7-11831 (1995), this type of a hinge device comprises a pair of hinge members which are connected with a device body and its cover non-rotatably respectively, a movable member which is connected non-rotatably with one of the hinge members mentioned above and movable in a direction of the rotation axis of such pair of the hinges, and an biasing means which presses the movable member against the other hinge member.
FIG. 15 shows a hinge member 1 of a conventional hinge device mentioned above. Three engaging cavities 1a, 1b, 1c extending in radial directions are formed on the end face of the hinge member with which the movable member 2 comes into contact. The engaging cavities 1a, 1b, 1c are arranged such that the engaging cavities 1b, 1c are separated in opposing directions by the same angle with respect to the engaging cavity 1a. On the other hand, as shown in FIG. 16, the end face of the movable member 2, which is pressed against the hinge member 1, has two contact projections 2a, 2b. These two contact projections 2a, 2b are arranged in such a way that they are separated by the same angle as the angle between the engaging cavities 1a, 1b in a circumferential direction from each other.
When the cover is positioned at the closed position, the contact projections 2a, 2b are engaged with the engaging cavities 1a, 1b respectively. When the cover is positioned at the open position, they are engaged with the engaging cavities 1c, la respectively. Actually, as shown in FIG. 15(B), the contact projections 2a (2b) come into contact with the side of the engaging cavities 1a (1b, 1c) so that the cover is kept at its closed or open position.
A pair of hinge devices which connect the cover with the device body rotatably are typically installed on the right and left sides of the device body. Assuming that a hinge member 1 and a movable member 2 as shown in FIGS. 15 and 16 are used for the hinge device which is installed on the right side of the device body, a conventional hinge device has the problem that at least the movable member 2 cannot be used for the hinge device to be installed on the left side, and a dedicated movable member for the left hinge device needs to be manufactured separately.
That is, in the case that the hinge member 1 and the movable member 2 are used for the right hinge device, when the cover is closed, the contact projections 2a, 2b are engaged with the engaging cavities 1a, 1b. When the cover is open, such contact projections 2a, 2b are engaged with the engaging cavities 1c and 1a. Therefore, when the cover rotates to the open position, as shown in FIG. 16, the movable member 2 rotates in the direction of arrow X. If the hinge member 1 and the movable member 2 are used for the left hinge device, when the cover rotates to the open position, the movable member 2 rotates in the direction of arrow Y. When the movable member 2 rotates in the direction of arrow Y, the contact projection 2b is engaged with the engaging cavity 1c on the way of rotation to the open position. Therefore, the cover cannot rotate smoothly. In addition, when the cover reaches its closed position, the contact projection 2b does not reach the engaging cavity 1a, so they cannot be engaged with each other. As a result, the contact projection 2a cannot also be engaged with the engaging cavity 1b. Therefore, it is necessary to form a contact projection 2c instead of the contact projection 2b, as shown with an imaginary line in the Figure on the movable member of the left hinge device. For this reason, in case of a conventional hinge device, the left and right hinges require a dedicated movable member 2. That is, a conventional hinge device requires two kinds of the movable member 2. As a result, the number of parts increases and the manufacturing cost increases.
To solve the above-mentioned problems, the present invention employs a hinge device for connecting a device body with its cover rotatably between its closed and open positions. The present invention comprises a pair of hinge members which are connected with said device body and said cover respectively and which are connected in such that they can rotate from each other about the rotation axis of said device body and said cover; a movable member which is connected with one of a pair of said hinge members non-rotatably, and which can move in the direction of said rotation axis; and biasing means which presses said movable member against the other hinge member, on one of contact faces of said other hinge member and said movable member which come into contact with each other, a pair of first conversion portions which are separated by 180 degrees from each other in a circumferential direction about said rotation axis, a pair of second conversion portions which are separated by 180 degrees from each other in a circumferential direction about the above-mentioned rotation axis and which are separated by a predetermined angle from said first conversion portions in a circumferential direction, and a pair of positioning cavities which are arranged at a center between said first conversion portion and said second conversion portion are formed; and on the other contact face, a pair of pressing projections are formed, the pair of pressing projections are separated by 180 degrees from each other in a circumferential direction about said rotation axis, come into contact with a pair of said first conversion portions to convert the force of said biasing means into a force for pressing said other hinge member from its open position side to its closed position side when the cover rotates closed position, come into contact with a pair of said second conversion portions to convert the force of said biasing means into a force for pressing said other hinge member from its closed position side to its open position side when the cover rotates open position, and fit into a pair of said positioning cavities to connect a pair of said hinge members with each other properly and non-rotatably; a bottom face defining said positioning cavities is formed by a concave spherical surface; an outer face defining said pressing projection is formed by a convex spherical surface having the same size of that of the concave spherical surface of said positioning cavities.
In this case, it is desirable that said first and second conversion portions are formed on both sides of the circumferential direction about said rotation axis of the bottom face of said positioning cavities. It is also desirable that said first and second conversion portions are formed by the concave spherical surface having the same size of that of said concave spherical surface defining said positioning cavities.
In addition, it is also desirable that said other hinge member is connected with said device body or said cover, and can rotate by a slight angle with respect to said device body or said cover. It is desirable that said other hinge member comprises a contact member which comes into contact with said movable member, and a support member for supporting said contact member against the force of said biasing means, and at least said contact member can rotate by a slight angle about said rotation axis with respect to said device body or said cover with which said other hinge member is connected.